Lumbar punctures, or spinal taps, are indicated for a variety of reasons. In infants, lumbar puncture is indicated in any infant with symptoms suggestive of meningitis (seizures, intractable vomiting and unexplained fever), and in the evaluation of neonatal intracranial bleeding. The infant must be held firmly in the lateral decubitus or sitting position. Generally, a 22 to 25 gauge needle is inserted into the L3-L4 or L4-L5 interspace. A sample of cerebrospinal fluid is collected for diagnostic testing.
In general, the lumbar puncture procedure is carried out by a physician with the aid of one or more other persons who hold the infant in a side-laying, sitting position with the back arched. This position provides the physician access to the spinal region from which the cerebrospinal fluid will be drawn. Stable, proper positioning of the patient is critical to a successful lumbar puncture. If the patient's back is over-arched, upward pressure can be exerted on the infant's diaphragm resulting in a compromise of the patient's respiratory status. Similarly, neurologic injury or unnecessary trauma can occur if the needle is inserted in the incorrect location.